Networking quantum networks with minimum cost aggregation

A quantum version of an internet, called a quantum internet, holds promise for achieving distributed quantum sensing and large-scale quantum computer networks, as well as quantum communication among arbitrary clients all over the globe. The main building block is efficient distribution of entanglement—entangled bits (ebits)—between arbitrary clients in a quantum network with error bounded by a constant, irrespective of their distance. In practice, this should be accomplished across multiple self-organising quantum networks, analogously to what the current internet does in conventional communication. Here we present a practical recipe on how to efficiently give arbitrary clients ebits with error bounded by a constant, regardless of their distance, across multiple quantum networks. This recipe is composed of two new concepts, minimum cost aggregation and network concatenation. Our recipe forms the necessary basis of designing a quantum internet protocol for networking self-organising quantum networks to make a global-scale quantum internet.